Light source device and surface light source device equipped with same

ABSTRACT

A light source device comprising: a point light source for emitting light; a light source substrate directly mounting the point light source; a light source substrate cover having a through hole or a notch in a position to which the point light source corresponds, the light source substrate cover arranged opposite to a surface of the light source substrate on which the point light source is mounted; and a support member for supporting the light source substrate, the support member arranged to be opposed to the reverse side of the mounting surface of the light source substrate, the support member has a substantially same size with the light source substrate; wherein the light source substrate cover and the support member sandwich the light source substrate to support the light source substrate.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a divisional of, and claims the benefit under35 U.S.C. §120 from U.S. application Ser. No. 13/422,059, filed on Mar.16, 2012, which is a divisional of U.S. application Ser. No. 12/022,669,filed Jan. 30, 2008, which claims priority under 35 U.S.C. §119 fromJapanese Patent Application No. 2007-021366, filed on Jan. 31, 2007, theentire contents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a light source device used forillumination of a display device or the like, and a surface light sourcedevice equipped with the light source device.

BACKGROUND

A general display device comprises a display panel, a circuit board, alight source device and the like. A light source device that irradiateslight from the rear surface thereof is either a side light type (edgelight type) including a light source on the side surface of an enclosureor a direct type including a light source on the bottom of an enclosurein a position opposed to a display panel.

Some of the side light type light source devices use a light guide platein order to guide light from a light source to an opening of anenclosure. A light source device using a light guide plate propagates,inside the light guide plate, light emitted from a linear light sourcesuch as a cold-cathode tube or a point light source such as a lightemitting diode (hereinafter referred to as an LED) and diffuses thelight by way of a diffusion pattern provided in the light guide plate totake out the light in the shape of a plane at the opening of theenclosure.

With a light source device using a point light source such as an LED asa light-emitting element described above, the luminance of a displayscreen is enhanced by increasing the number of point light sources thusincreasing an element density or increasing the current supplied to eachpoint light source. In any way, heat from each point light source causedby light emission brings the periphery of the point light source at hightemperature.

There is proposed a light source device including a light sourcesubstrate mounting heat-dissipating means, the light source substratecomposed of a flexible printed circuit board (hereinafter referred to asan FPC) mounting point light sources and a wiring pattern to feed powerto each light source (for example, Patent Reference 1 (JapanesePublished Unexamined Patent Application No. 2006-210183) and PatentReference 2 (Japanese Published Unexamined Patent Application No.2002-229022)). A surface lighting device 1 disclosed in Patent Reference1 is arranged so that a heat-transmitting part 10a provided in arecessed part 10 formed on the side wall 8 of a frame 6 made of ametallic material will come into contact with a mounting surface 3d ofeach of the point light sources 3 thus receiving the light sources 3 inthe recessed part 10. An FPC 4 as a light source substrate and the pointlight sources 3 are fixed together with a conductive adhesive 12. Thetechnique disclosed in Patent Reference 1 uses this arrangement toefficiently transmit heat generated by the light emission of the pointlight source 3 by way of a metallic frame 6 thus enhancing the heatdissipation, which allows the element density of the point light source3 and the current supplied to each point light source 3.

In a backlight device disclosed in Patent Reference 2, a soft metallicsheet 7 for dissipating heat from a light-emitting diode 2 formed inalmost the same shape as a film wiring board 4 is bonded with adhesiveto a surface opposite to the surface of the film wiring board 4 on whichthe light-emitting diode 2 is mounted, thus covering a metallicreflector 8. The technique disclosed in Patent Reference 2 uses thisarrangement to effectively transmit heat generated on the light-emittingdiode 2 as a light source to the film wiring board 4 and aheat-dissipating member such as the soft metallic sheet 7 withoutletting the heat fill the backlight device itself.

However, the light source devices disclosed in Patent Reference 1 andPatent Reference 2 have following disadvantages. For example, although alight source substrate and a heat-dissipating member are fixed togetherwith an adhesive, the adhesive peels off over time.

When a metallic plate such as an MCPCB (Metal Core Printed-CircuitBoard) is used for a light source substrate in order to prevent thepeel-off, the resulting cost is higher than that of using an FPC.

-   [Patent Reference 1] JP-A-2006-210183 (Pages 2-5, FIGS. 1-4)-   [Patent Reference 2] JP-A-2002-229022 (Pages 3-7, FIGS. 1-4)

SUMMARY

The invention has been accomplished in order to solve the problems andis capable of efficiently dissipating heat from a light source substratedirectly mounting a point light source. The invention provides a lightsource device capable of firmly fixing a light source substrate and aheat-dissipating part to each other. The invention further provides asurface light source device mounting the light source device having astructure whereby the light source device is readily replaced with sparewithout breakage or a wire break.

The invention provides a light source device comprising: a point lightsource for emitting light; a light source substrate directly mountingthe point light source; a light source substrate cover having a throughhole or a notch in a position to which the point light sourcecorresponds, the light source substrate cover arranged opposite to asurface of the light source substrate on which the point light source ismounted; and a support member for supporting the light source substrate,the support member arranged to be opposed to the reverse side of themounting surface of the light source substrate, the support member has asubstantially same size with the light source substrate; wherein thelight source substrate cover and the support member sandwich the lightsource substrate to support the light source substrate.

The light source device according to the invention comprises: a lightsource substrate directly mounting a point light source for emittinglight; a light source substrate cover including a through hole or anotch in a position to which the point light source corresponds, thelight source substrate cover arranged opposite to the surface of thelight source substrate on which the point light source is mounted; and asupport member for supporting the light source substrate, the supportmember arranged opposing a surface opposite to the mounting surface ofthe light source substrate; characterized in that the light sourcesubstrate cover and the support member sandwich the light sourcesubstrate to support the same. This arrangement efficiently dissipatesheat from a light source substrate mounting a point light source.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative aspects of the invention will be described in detail withreference to the following figures wherein:

FIG. 1 is an exploded perspective view of a display device according toEmbodiment 1 of the invention;

FIG. 2 is a cross-sectional view of a surface light source deviceassumed in case the display device in FIG. 1 is assembled, taken in thedirection of arrow A-A;

FIG. 3 is an exploded perspective view of a light source deviceaccording to Embodiment 1 of the invention;

FIG. 4 is an enlarged view of main parts of the light source deviceaccording to Embodiment 1 of the invention in an assembled state;

FIG. 5 is a cross-sectional view of the light source device in FIG. 4taken in the direction of arrow B-B;

FIG. 6 is an enlarged view of main parts of the light source deviceaccording to Embodiment 1 of the invention;

FIG. 7 is an exploded perspective view of a surface light source deviceaccording to Embodiment 1 of the invention;

FIG. 8 is an enlarged view of main parts of the light source deviceaccording to Embodiment 1 of the invention;

FIG. 9 is an enlarged view of main parts of the light source deviceaccording to Embodiment 1 of the invention;

FIG. 10 is an enlarged view of main parts of the light source deviceaccording to Embodiment 1 of the invention;

FIG. 11 is an exploded perspective view of a display device according toEmbodiment 2 of the invention; and

FIG. 12 is a cross-sectional view of the display device in FIG. 11 in anassembled state taken in the direction of arrow E-E.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the invention concerning the configuration of adisplay device according to the invention and a method for manufacturingthe display device will be described referring to drawings. Same signsused across the drawings show substantially the same configuration.

Embodiment 1

FIG. 1 is an exploded perspective view showing a general configurationof a display device according to the invention. FIG. 2 is across-sectional view of the display device in FIG. 1 in an assembledstate taken in the direction of arrow A-A. FIG. 3 is an explodedperspective view showing a general configuration of a light sourcedevice mounted on the display device according to the invention. FIG. 4is an enlarged view of main parts of the light source device in anassembled state. FIG. 5 is a cross-sectional view of the light sourcedevice in FIG. 4 taken in the direction of arrow B-B.

Embodiment 1

As shown in FIG. 1 or 2, a numeral 1 represents a box-shaped rear frame1 having an opening 1 a. A light source device 31 for emitting light isarranged on an inner side surface 1 b as a side surface of the innerwall of the rear frame 1. A reflector 2, which guides light emitted fromthe light source device 31 toward the opening 1 a, is arranged on thebottom surface 1 c of the inner wall of the rear frame 1. An almostrectangular light guide plate 7 for propagating, in the shape of aplane, light emitted from the light source device 31 is arranged insidethe rear frame 1. An incidence surface 7 b as a side surface of thelight guide plate 7 is arranged in a position opposite to alight-emitting part 31 a of the light source device 31 from which lightis emitted. The rear frame 1 is fitted to a front frame 8 including anopening to provide a surface light source device 32. A display panel 9and a circuit board 10 for driving and controlling the display panel 9are arranged on the exit surface of the surface light source device 32.A front frame 11 including an opening 11 a is fitted to the surfacelight source device 32 to provide a display device 33.

Next, the light source device 31 according to Embodiment 1 will bedetailed referring to drawings. As described earlier, in FIG. 1, thelight source device 31 is arranged on the inner side surface 1 b of therear frame 1. As shown in FIGS. 3 and 4, the light source device 31includes an almost rectangular light source substrate 4 on which pointlight sources 3 are mounted, a light source substrate cover 5 arrangedon the surface 41 of the light source substrate 4 mounting the pointlight sources 3, and a support member 6 arranged opposite to a rearsurface 42. The point light source 3 is made of, for example, alight-emitting diode for emitting light of red, green, blue, or whitecolor or an intermediate color thereof. A single point light source or aplurality of point light sources 3 is arranged and mounted on the lightsource substrate 4 via soldering. In case plural point light sources 3are mounted, a particular color of light may be selected depending onthe application. A combination of colors may be selected as required.The point light sources 3 may be arranged in desired positions and withdesired spacing depending on the application or purpose. In Embodiment1, plural point light sources 3 are mounted on the light sourcesubstrate 4 in an almost straight line and with same spacing.

As shown in FIGS. 2 to 4, the light source substrate 4 of the lightsource device 31 includes a recessed part 4 a in a position where aprojection 5 b provided on a light source substrate cover 5 and arecessed part 6 a provided on the support member 6 overlap one on theother. The light source substrate 4 may be a glass epoxy substrate,metal base substrate, a flexible substrate or the like. A wiring pattern(not shown) for feeding power to the point light sources 3 is arrangedon the light source substrate 4.

As shown in FIGS. 2 to 5, the light source substrate cover 5 is arrangedon the surface 41 of the light source substrate 4 mounting the pointlight sources 3. Through holes 5 a are formed on the light sourcesubstrate cover 5, and the through holes 5 a are formed in a positionwhere the through holes 5 a is arranged opposite to the point lightsources 3 on the light source substrate 4. A projection 5 b protrudingfrom a rear surface 52 is arranged between the through holes 5 a, andarranged on the side of a top surface 53 and a bottom surface 54. Asshown in FIG. 5, the projection 5 b comprises a tip 5 c fitted in arecessed part 6 a provided on the support member 6. As shown in FIG. 2,by forming the light source substrate cover 5 thicker than the pointlight source 3 so that the point light source 3 mounted on the lightsource substrate 4 will not protrude from the through hole 5 a, asdescribed below, it is possible to prevent the point light source 3 frombeing damaged while being in contact with the rear frame 1, front frame2, light guide plate 7 or the like upon assembling the light sourcedevice 31 into the display device 32 or in an attempt to remove thelight source device 31. The through hole 5 a may be a notch and may haveany shape as long as the shape receives a light source. The light sourcesubstrate cover 5 is made of a plastic resin, a metal, or a materialincluding a metallic material. The light source substrate cover 5 may beformed of a single member or a combination of plural members. The lightsource substrate cover 5 desirably includes a surface formed of a highreflection member in a white color or having a mirror surface so thatlight emitted from the point light source 3 is directed to the lightguide plate 7.

As shown in FIGS. 2 to 5, the support member 6 is formed in the samesize equal to or larger than that of the light source substrate 4 andarranged on the side of the rear surface 42 of the light sourcesubstrate 4 thus preventing warp or displacement of the light sourcesubstrate 4. The top surface 61 and bottom surface 62 of the supportmember 6 are provided with recessed parts 6 a for fitting to the lightsource substrate cover 5. As shown in FIGS. 3 and 5, the recessed part 6a is a recessed part 6 a with a different step height on the frontsurface 63 or on the rear surface 64, and the recessed part 6 a isformed so that the projection 5 b and the tip 5 c of the light sourcesubstrate cover 5 will not protrude from the rear surface 64 and the topsurface 61 of the support member 6. While the support member 6 may beformed of a plastic resin, the support member 6 may be formed of a metalwith high thermal conductivity including aluminum, stainless steel, ironor copper, or a material including such a metal in order to enhance theheat dissipating effect. The support member 6 may be formed of a singlemember or a combination of plural members.

Next, a method for assembling the light source device 31 will bedescribed referring to FIG. 3. First, the light source device 31 isarranged so that the rear surface 42 of the light source substrate 4mounting the light sources 3 will overlap the front surface 63 of thesupport member 6. Next, arrangement is made so that the recessed part 4a of the light source substrate 4 will match the recessed part 6 a ofthe support member 6. Next, the through holes 5 a of the light sourcesubstrate cover 5 are arranged so as to fit over the point light sources3. The projection 5 b is aligned with the position of the support member6 where the recessed part 6 a of the support member 6 is formed and theprojection 5 b and the tip 5 c are fitted in the recessed part 6 a. Inthis procedure, a double-faced tape, an adhesive, or grease with highthermal conductivity may be used to fix the light source substrate 4 tothe support member 6. This enhances adhesion of the light sourcesubstrate 4 to the support member 6 thus improving the heat dissipation.Even in case an adhesive is degraded over time, it is possible to firmlyfix the light source substrate 4 and the support member 6 together byfitting and fixing the members to each other.

As shown in FIGS. 3 and 5, in the light source device 31, at least twofitting parts formed of the projection 5 b and the tip 5 c of the lightsource substrate cover 5, the recessed part of the light sourcesubstrate 4, and the recessed part 6 a of the support member 6 areformed at each member to fix the members. By arranging the fitting partsin four positions, that is, two positions on the top surface (53, 61)and two positions on the bottom surface (54, 62), fixing of the membersare made reliable.

While the projection 5 a and the tip 5 c for fitting are provided on thelight source substrate cover 5 and the recessed part 6 a for fitting isprovided on the support member 6 in this embodiment, the recessed partmay be provided on the light source substrate cover 5 and the projectionand tip may be provided on the support member 6. In this way, thepositions and numbers of fitting parts may be arbitrarily changed.

As shown in FIG. 6, a projection 5 d for positioning is arranged on thelight source substrate cover 5 and positioning holes for the projection5 d are provided in the light source substrate 4 (4 b) and the supportmember 6 (6 b). They are separately from the above-described fittingpart and positioning. By forming the projection for positioning andcorresponding positioning holes and performing positioning, it ispossible to prevent displacement of the light source substrate cover 5,light source substrate 4 and support member 6 that could occur in theprocess of assembling the light source device 31 and the process ofassembling the display device 33. While a projection is provided on thelight source substrate cover 5 in this example, positions and shapes ofa projection for positioning and positioning holes may be changed asrequired. For example, a projection may be provided on the supportmember 6.

Next, a method for assembling the light source device 31 of Embodiment 1into the display device 33 will be described. FIG. 7 is an enlarged viewof main parts assumed when the light source device 31 is assembled intothe surface light source device 32.

As described above, in the light source device 31, the light sourcesubstrate cover 5 and the support member 6 sandwich the light sourcesubstrate 4 to support the same so as to firmly fix the light sourcesubstrate 4 and the support member 6 together. It is thus possible tomove the light source device 31 along the inner side surface 1 b of therear frame 1 to assemble the light source device 31 into the surfacelight source 32. Before the light source device 31 is assembled alongthe inner side surface 1 b, a through hole 12 for inserting the lightsource device 31 is formed in the side surface 1 d of the rear frame 1and the side surface of the front frame 8 of the surface light sourcedevice 32. The light source device 31 is inserted from the through hole12, along the inner side surface 1 b of the rear frame 1 in thedirection of arrow C. In case the light source device 31 is faulty andmust be replaced with spare, the light source device 31 may be readilyremoved by pulling it out of the through hole 12 in the direction ofarrow D. In FIG. 1, if wishing to arrange the light source device 31 ina replaceable fashion in the display device 33, a through hole is formedin the front frame 11 in a position corresponding to the through hole12.

As described above, the light source device 31 according to theinvention includes a light source substrate 4 mounting the light sources3. The light source substrate cover 5 is arranged on the surface 41 ofthe light source substrate 4 mounting the point light sources 3. Thesupport member 6 is arranged on the rear surface 42. The light sourcesubstrate cover 5 and the support member 6 sandwich the light sourcesubstrate 4 to support the same, which prevents deformation of or slackin the light source substrate 4 and efficiently transmits heat from thepoint light sources 3 to the support member 6. The projection 5 b andthe tip 5 c of the light source substrate cover 5 are matched with theposition of the support member 6 where the recessed part 6 a is formed.The projection 5 b and the tip 5 c are fitted in the recessed part 6 aand the members are fixed together, thus firmly fixing the light sourcesubstrate 4 to the support member 6. Further, the light source device 31may be inserted/removed into/from the through hole 12 provided in thesurface light source device 32. It is thus possible to readily replacethe light source device 31 with spare in case the light source device 31has gone faulty.

As shown in the enlarged view of main parts of FIG. 8, as a variation ofthe light source device 31 of this embodiment, a tapered part 5 g isprovided at the through hole 5 a of the light source substrate cover 5for receiving the point light source 3. The tapered part 5 g is arrangedon the inner side surface forming the through hole 5 a provided in thelight source substrate cover 5, so as to slant the through hole 5 a andenlarge the same from the rear surface 52 as a surface opposite to themounting surface 41 of the light source substrate 4 toward the frontsurface 51 as a surface opposite to the rear surface 52. When the lightsource device 31 including the tapered part 5 g is assembled into thedisplay device 33 shown in FIG. 1, light emitted from the point lightsource 3 may be reflected on the tapered part 5 g to be directed to thelight guide plate 7. This eliminates reflection losses at the lightsource substrate cover 5 and efficiently causes light emitted from thepoint light source 3 to be incident on the light guide plate 7.

As shown in the enlarged view of main parts of FIG. 9, as anothervariation of the light source device 31 of this embodiment, a chamferedpart 5 f is formed at an end of the light source substrate cover 5. Thechamfered part 5 f is formed at the insertion-starting end of the lightsource substrate cover 5 before the light source device 31 is insertedfrom the through hole 12 so as to enhance the workability. Further, asshown in FIG. 10, a projecting part 5 e is arranged at an end of thelight source substrate cover 5 where insertion of the light sourcedevice 31 is finished. By arranging the projecting part 5 e, it ispossible to prevent leakage of light from the through hole 12 as well ascause light destined to the projecting part 5 e to reflect toward thelight guide plate 7.

While the light source device 31 is arranged on one side of the innerside surface 1 b of the rear frame 1 in this embodiment, the lightsource devices 31 may be arranged on two to four sides to enhance andmake uniform the luminance.

The rear frame 1 is made of a metal with high thermal conductivityincluding aluminum, stainless steel, iron or copper, or a plastic resin.The rear frame 1 may be composed as a single member or a combination ofplural members as required.

The front frame 8 is made of a metal with high thermal conductivityincluding aluminum, stainless steel, iron or copper, or a plastic resin.The front frame 8 may be composed as a single member or a combination ofplural members as required.

A display panel 9 may be a liquid crystal panel. A liquid crystal panelis composed of a pair of reflectors sandwiching in a bonding fashion apair of glass substrates (top and bottom) which are sealed with asealant and between which a liquid crystal is injected. The displaypanel 9 is coupled to a circuit board 10, such as a flexible substrateon which a driving IC chip is mounted, for driving and controlling thedisplay panel 9.

An optical sheet such as a diffusion sheet, a prism sheet or apolarization reflection sheet, or a plate-shaped light diffusion memberis arranged between the display panel 9 and the light guide plate 7 inorder to enhance the display performance.

The material of the light guide plate 7 is generally a highlytransparent material such as PMMA (Polymethylmethacrylate) or PC(Polycarbonate). It is favorable to provide a certain amount of distancebetween the point light source 3 and the light guide plate 7 in order toprevent degradation of the light guide plate 7 attributable to heat fromthe point light source 3 in use under high temperatures. As inEmbodiment 1, it is possible to provide a certain amount of distancebetween the point light source 3 and the light guide plate 7 byproviding the light source substrate cover 5 with a thickness greaterthan that of the point light source 3.

Embodiment 2

FIG. 11 is an exploded perspective view of a display device showingaccording to Embodiment 2 of the invention. FIG. 12 is a cross-sectionalview of the display device in FIG. 11 in an assembled state taken in thedirection of arrow E-E. As shown in FIGS. 11 and 12, a light sourcedevice 34 in Embodiment 2 includes a support member 6 arranged on therear surface 42 of the light source substrate 4 but does not include alight source substrate cover 5 such as one in Embodiment 1 arranged onthe surface 41 of the light source substrate 4 mounting point lightsources 3. The light source device 34 is fitted to a projection ifformed on the rear frame 1 and a recessed part 8 b formed of the rearframe 1 and a front frame 8 to support the light source substrate 4 andthe support member 6. Embodiment 2 is different from Embodiment 1 onlyin that the light source device 34 is fitted to the projection if formedon the rear frame 1 and the recessed part 8 b formed of the rear frame 1and the front frame 8 to support the light source substrate 4 and thesupport member 6. The remaining configuration is the same as that ofEmbodiment 1.

In FIGS. 11 and 12, a projection if is formed on part of a bottomsurface 1 c opposite to the opening 1 a of the rear frame 1, and theprojection 1 f includes one side of the bottom surface 1 c and formsconvex from inside to outside. By fitting the light source device 34 tothe inner wall of the projection 1 f, the light source substrate 4 andthe support member 6 are supported. In the process, the support member 6is arranged opposite to the inner side surface 1 b of the rear frame 1.The mounting surface 41 of the light source substrate 4 is arrangedopposite to a support part 1 e forming part of the projection 1 f.

A recessed part 8 b is formed of an inner side surface 1 b of the rearframe 1 and part of the side surface 8 a of the front frame 8 having aside surface 8 a arranged in opposite position and fitted to the innerside surface 1 b of the rear frame 1. The light source device 34 isfitted in the recessed part 8 b. The mounting surface 41 of the lightsource substrate 4 is arranged opposite to the support part 8 c formedat the recessed part 8 b and fits, together with the inner side surface1 b of the rear frame 1, the light source substrate 4 and the supportmember 6 and supports them.

The method for assembling the light source device 34 into the surfacelight source device 32 according to Embodiment 2 fits the light sourcedevice 34 to the inner wall of the projection 1 f formed on part of thebottom surface 1 c of the rear frame 1. In the process, the supportmember 6 is arranged opposite to the inner side surface 1 b of the rearframe 1. The mounting surface 41 of the light source substrate 4 isarranged opposite to a support part 1 e forming part of the projection.Next, a reflector 2 and a light guide plate 7 are arranged. The frontframe 8 is fitted to the rear frame 1 and the light source device 34 isfitted in the recessed part 8 b.

As described above, the surface light source device 32 according toEmbodiment 2 forms, on part of a bottom surface 1 c opposite to theopening 1 a of the rear frame 1, a projection 1 f including one side ofthe bottom surface 1 c and becoming convex from inside to outside andfits the light source device 34 in the recessed part 8 b to the innerwall of the projection 1 f and in the recessed part 8 b formed of therear frame 1 and the front frame 8. This firmly fixes the light sourcesubstrate 4 and the support member 6.

The projection 1 f formed on the bottom surface 1 c of the rear frame 1may be arranged along the light source substrate 4 or support part ofthe light source substrate 4. In Embodiment 2, while the light sourcedevice 34 is supported by fitting the light source device 34 to theprojection if formed on the rear frame 1 or in the recessed part 8 bformed of the rear frame 1 and the front frame 8, any shape may be usedas long as the shape allows fitting of the light source device to therear frame 1 and the front frame 8. The position where the recessed part8 b is formed may be changed in various ways.

The support member 6 may be fixed to the rear frame 1 via a screw or anadhesive so as to dissipate heat from the light source substrate 4 viathe support member 6.

What is claimed is:
 1. A surface light source device comprising: a rearframe; a support member fixed to the rear frame; a light sourcesubstrate including a mounting surface, on which a point light source ismounted, and a rear surface fixed to the support member; and a frontframe including a recessed part arranged opposite to a part of themounting surface, and a side part formed in a succession of the mountingsurface, wherein the rear frame and the front frame support the lightsource substrate and the support member.
 2. The surface light sourcedevice according to claim 1, wherein the support member is fixed to therear frame by using at least one of a screw and an adhesive to dissipateheat from the light source substrate via the support member.
 3. Thesurface light source device according to claim 1, wherein the supportmember includes at least one of a projection for positioning and apositioning hole for positioning.
 4. The surface light source deviceaccording to claim 1, wherein a projection is formed on part of thebottom surface of the rear frame, which forms convex from inside tooutside, and the support member is fitted between the inner side of theprojection of the front frame and the recessed part of the rear frame.5. A display device comprising: a surface light source device; and adisplay panel arranged at an emitting side of the surface light sourcedevice, the surface light source device further including a rear frame,a support member fixed to the rear frame, a light source substrateincluding a mounting surface, on which a point light source is mounted,and a rear surface fixed to the support member, and a front frameincluding a recessed part arranged opposite to a part of the mountingsurface and a side part formed in a succession of the mounting surface,wherein the rear frame and the front frame support the light sourcesubstrate and the support member.